A LEADING environmental group last night warned Liverpool council that the city's proposed smoking ban could cause a widespread problem with litter.

The news comes after a study, , commissioned by the Industry Council for Packaging and the Environment (INCPEN), found cigarette debris was the highest cause of litter after chewing gum.

The report, which examined 58,000 instances of littering in 390 locations round the UK, found cigarette ends accounted for one third of all litter.

An INCPEN spokesman said: "The proportion of cigarette ends littered increased by 43.5% between 1996 and 2004 as more places started to ban smoking, forcing smokers to congregate on street corners and pavements.

"This figure is likely to rise in Liverpool if the city follows Ireland's example of banning smoking in public places - a proposal which has been put forward."

"They need to put the necessary ashtrays and bins in place, to ensure the familiar groups of smokers huddled outside offices and bars do not become an even bigger litter problem."

The survey was carried out by Encams, the charity which runs the Keep Britain Tidy campaign.

Peter Gibson, spokesman for the campaign, said: "We don't have a view on smoking, but we are concerned that when offices brought in a ban very few employers provided bins for their employees to use and the net result was more were dumped on the ground.

"You are not going to get people to stop smoking overnight so we are planning a big campaign this year to focus on the issue."

He said he believed the onus should be on pubs to provide ashtrays and bins.